It is well known to provide an X-ray tube comprising an electron source and a metal anode, wherein the anode is at a positive potential with respect to the electron source. The electric field accelerates the emitted electron towards the anode. When they strike the anode they lose some, or all, of their kinetic energy, the majority of which is released as heat. This heat can reduce the target lifetime and it is therefore common to cool the anode. Conventional methods include air cooling, wherein the anode is typically operated at ground potential with heat conduction to ambient through an air cooled heatsink, and a rotating anode, wherein the irradiated point is able to cool as it rotates around before being irradiated once more.
In some circumstances a moving X-ray source is required, which is generated by scanning an electron beam along an arcuate or linear anode. These anodes may extend to a length of several meters and it is generally complex and expensive to fabricate a single piece anode.